
Bad posture has been blamed for every possible ailment of the human condition, but most particularly for those common musculoskeletal problems such as backache, headaches and muscle fatigue. Most everybody remembers their mother telling them to “stop slouching” or “sit up straight” at some point during their teenage years (or even later!).
But what is “Good Posture” as opposed to “Bad Posture”? What is posture anyway? If my posture is bad, how do i fix it?
Posture can be defined as a body’s position in space (or more specifically, under gravity). So how efficiently a body stands up to gravity can be regarded as being representative of how good or bad its posture is. In other words, a body that efficiently bears gravity doesn’t tire as easily, and its muscles don’t fatigue as fast. Conversely, a body that doesn’t efficiently resist gravity (e.g. slouching) requires its postural muscles to fire more intensely and continuously which leads to “burn-out”.
Muscles that are in a continuous state of activation experience decreased blood flow, oxygenation and glucose circulation, while simultaneously building up levels of Lactic acid and other irritants within the tissues. Ligaments under excessive load become irritable, sprained and unstable. All this leads to stiff and aching muscles, eventually leading to trigger points that can refer burning, pins and needles or pain into the head, arms or rest of the body.
So what does “good posture” look like?

Most people think good posture involves standing up straight, with shoulders back, chin up and chest forward, just like a soldier on parade. However, anyone who has tried to maintain that posture for any length of time can quickly relate how this made them as sore as they were before, since it is hard to maintain for any length of time.

Consider the posture of those famous Spanish dancing stallions. While watching them prance around in a show is a beautiful sight, it is not how they behave in nature. Most of the moves they are taught are unnatural to them, though they may have served some historically useful military or other purpose. When you watch them in a paddock, away from their trainer, they don’t look the same nor do they parade around all day. They have a much more “casual” posture. They still look graceful, but they are not in a rigid or militaristic pose, unless they are defending territory or asserting their dominance over other horses. Similarly with humans, a militaristic pose might look nice at first or present an image of dominance or assertiveness, but it takes a lot of energy to maintain, so is not in itself “natural” for a relaxed state. Good posture (efficient movement through space) depends on you maintaining your weight as close as possible to your “Centre of Gravity line”.

The man on the left is in a classic “Military Posture”. While his Centre of Gravity line runs down from the centre of the skull and ear, note how it doesn’t pass through the low-back vertebrae, but slightly behind them. This makes him lean ever so slightly forward, which reflexly fires his calf and back muscles to keep him from going too far forward. Also note how the line continues down slightly behind his hip joint. His pelvis is tilted forward and his hip has rolled forward to try and keep him balanced. The elevation of his chest and shoulders, and forward tilting of his pelvis has put a strain on his abdominal muscles as well as his hamstrings. The line then continues somewhat in front of his knee, resulting in excess extension strain at the knee joint, with tight, sore quadriceps (front thigh muscles), calf muscles, Achilles tendon strain and possible future ankle and foot problems. Obviously this kind of posture is not meant to be sustained for long periods, but in situations of life or death, may help him accelerate forward quickly to challenge a rival or stand his ground from a frontal attack. Not very relaxing and definitely hard to maintain for long.
Below are a couple of examples of common postures as they compare to a biomechanically ideal one (A).

Notice in diagram (A) how the centre of gravity line passes from the centre of the top of the skull, through the ear hole, through the hip joint and into the knee and ankle, while in B,C,and D the line does not go through the centre of the skull, the ear hole or the hip joints. Diagram B is an example of a common posture in modern man called “Lower Cross Syndrome”. For a further discussion on this particular postural fault and its management go here
So how do I fix my posture?
First of all, BE RELAXED! You will never fix your posture if you have to work hard at it. If you try to maintain some preconceived notion of what “looks proper”, you will only fatigue faster and go back to slouching very quickly. The trick is to let your brain do all the work, and to use subconscious programming to make those changes more permanent. Then you must reinforce those changes through exercises that stretch, strengthen and stimulate positional awareness in postural muscles. Try to appreciate that the modern dependence on prolonged sitting since early childhood and throughout your life causes far reaching consequences in terms of imbalanced muscles, bone growth and nerve pressure. You can’t fix this type of problem quickly!